Expression of genes for the Epstein--Barr virus small RNAs EBER-1 and EBER-2 in Daudi Burkitt's lymphoma cells: effects of interferon treatment

Abstract

The relative levels, rates of synthesis and stabilities of the abundant Epstein-Barr virus (EBV)-encoded small RNAs, EBER-1 and EBER-2, were examined in Daudi Burkitt's lymphoma cells. Although both RNAs are transcribed at approximately equal rates, the steady-state level of EBER-1 is at least 10-fold greater than that of EBER-2. This is shown to be due to a much faster rate of turnover of EBER-2. In the presence of actinomycin D, the half-lives of EBER-1 and EBER-2 are 8 to 9 h and 0.75 h, respectively. Following treatment of the cells with human interferon (IFN) alpha the transcription of both RNAs is strongly inhibited. However, the level of EBER-1 increases up to twofold, indicating a further stabilization of this RNA. In IFN-treated cells, EBER-2 accumulates in the form of truncated products. Nuclease protection experiments indicated that this is due to a post-transcriptional modification of the 3' end of the molecule. These data show that the effects of IFN treatment on the expression of these two viral gene products are very complex in cells latently infected with EBV.